Coil stripping chisel



April 6, 1965 P. STRAKA 3,175,396

COIL STRIPPING CHISEL Filed June 14, 1963 INVENTOR WhY/f {kW h, pd/h[Zr/1r United States Patent O 3,176,396 COIL STRIPPIN G CHISEL PhilipStraka, Portland, reg., assignor to Crown Indus- This invention relatesto a coil stripping chisel of the type used to cut the coils of anelectric motor.

One purpose of the invention is a coil stripping chisel I of the typedescribed which will cut the motor coils without scarring or otherwisedamaging the motor laminations.

Another purpose is a chisel of the type described, the cutting edge ofwhich is shaped to bunch the wires in a coil so that they may be moreeasily cut.

Another purpose is a coil stripping chisel in which the cutting edge isprotected from dulling.

Another purpose is a coil stripping chisel of the type described whichis so formed that it may be inserted down below the edge of a motorcasing to cut the coils.

Another purpose is a chisel of the type described which is so formedthat it will not damage the motor casing.

Other purposes will appear in the ensuing specification, drawings andclaim.

The invention is illustrated diagrammatically in the following drawingswherein:

FIGURE 1 is a side view of the lower end of a coil stripping chisel,

FIGURE 2 is a top plan view of a portion of the chisel shown in FIGURE1,

FIGURE 3 is a top plan view of a motor illustrating the operation or useof the chisel shown in FIGURES 1 and 2, and

' FIGURE 4 is a section along plane 4-4 of FIGURE 3.

The chisel may include a shank which may be formed either for use with ahand tool, such as a hammer, or for use with an air hammer or the like.The particular configuration of the shank is not important. At the endof the shank 10 is a working end indicated generally at 12 whichgradually merges into the shank 10, as indicated by the curved surfaces14 and 16. The width of the working end section, as indicated in FIGURE2, is generally the same as the width of the shank, although this mayvary depending upon the type of shank. The end section 12 may have anupper fiat surface 18 and a lower surface 20, with these surfacesgradually coming together or tapering toward a blunted end 22. Asclearly shown in FIGURE 1, the blunted end 22 is rounded, as at 24, so

that there will be no sharp point or edges for scarring the motorlaminations or side of the motor casing.

A crescent-shaped recess 26 may be formed at the end of the tool and mayinclude a crescent-shaped lower cutting edge 28 and an uppercrescent-shaped edge 30,

, there being a slanted crescent-shaped surface 32 connecting the upperand lower crescent-shaped edges. ,As shown in FIGURE 1, the slantedsurface 32 forms an angle with the upper flat surface 18.

Considering FIGURES 3 and 4, a typical electric motor is indicatedgenerally at 34, the stator of which may include a stack of laminations36 with a plurality of coils 38 extending down through openings 40 inthe laminations. The motor casing 42 extends upwardly beyond the upperedge of the laminations.

In operation, the chisel will be placed, as indicated particularly inFIGURE 4, with its crescent-shaped lower cutting edge 28 against thewires coming from a particular opening 40 in the laminations. Note thatthe chisel extends across the motor casing and is effective to cut coilsat the side of the stator opposite that of the workman. As most motorcasings extend upwardly beyond the laminations, as indicated in FIGURE4, it is necessary for the working end of the chisel and the shank toform an obtuse angle or an angle such that the chisel may get down belowthe motor casing to work on the coils.

Of importance is the fact that the lower surface 20 of the end section12 is generally flat. The surface must be fiat in order for the chiselto slide along the laminations and cleanly cut the coils close to thelaminations. Also of importance is the fact that the end of the chiselis blunted and has lower rounded edges. This is done so that there willbe no scarring of the laminations as the chisel slides over them. It isof course important that the laminations remain untouched if the motoris to be rewired and reused. Also, the blunted edges will prevent themotor casing from being cut.

It is important that the surface 32 be slanted or formed at an anglewith the surface 18 to pull the chisel down tight against thelaminations. The wires being cut exert a downward force on the slantedsurface and tend to hold the chisel tight against the laminations for aclean cut.

The cutting edge 28 is crescent-shaped for a particular reason. As thetool moves into a group of wires, the crescent-shaped recess will tendto bunch the wires and to form a somewhat solid bar or rod out of them,as they could move about. By bunching the wires with the crescent-shapedrecess, it is possible to cut a greater number of wires in one cut.

The crescent-shaped cutting edge is important in that I it keeps thecutting edge away from the end of the chisel and there is no possibilityof dulling the cutting edge when the chisel strikes the side of a motorcasing. This also prevents the motor casing from being scarred by thechisel.

Whereas the preferred form of the invention has been shown and describedherein, it should be realized that there are many modifications,substitutions and alterations thereto within the scope of the followingclaim.

I claim:

A coil stripping chisel including a shank and an integral working endsection forming an obtuse angle therewith, said end section graduallymerging and curving into said shank and tapering from a thicknessapproximating that of the shank down to a rounded, blunted, relativelythin end, the top and bottom surfaces of said end section beinggenerally flat with said fiat surfaces merging into said thin, rounded,blunted end, a crescent-shaped recess in said end forming a lowercrescent-shaped cutting edge in said bottom flat surface, the upper edgeof said crescentshaped recess extending further from said blunted endthan said lower cutting edge, with a crescent-shaped slanted surfacebeing formed between said upper and lower crescent shaped edges, saidslanted surface forming an angle with the upper flat surface of theworking end section, said crescent-shaped recess extending inwardly fromsaid blunted end to define a pair of spaced rounded blunted ends adaptedto be pushed against the side of a motor casing or the like.

References Cited by the Examiner UNITED STATES PATENTS 1,404,650 1/ 22Richard -24 2,757,452 8/56 Barnes 30-168 2,960,767 11/ 60 Vonhofi' et a130-168 X FOREIGN PATENTS 110,565 5/00 Germany. 208,017 3/60 Austria.

WILLIAM FELDMAN, Primary Examiner. MILTON S. MEHR, Examiner.

